diff --git a/.github/workflows/cd-sam.yaml b/.github/workflows/cd-sam.yaml
index 9db958a..e5a53d3 100644
--- a/.github/workflows/cd-sam.yaml
+++ b/.github/workflows/cd-sam.yaml
@@ -23,14 +23,13 @@ on:
         description: "CloudFormation execution role ARN"
         type: string
         required: true
-      parameter-overrides:
-        description: "SAM parameter overrides (e.g. 'Key1=Value1 Key2=Value2')"
-        type: string
-        default: ""
     secrets:
       deploy-role-arn:
         description: "OIDC deploy role ARN"
         required: true
+      parameter-overrides:
+        description: "SAM parameter overrides (e.g. 'Key1=Value1 Key2=Value2')"
+        required: false
 
 permissions:
   id-token: write
@@ -60,8 +59,8 @@ jobs:
       - name: SAM deploy
         run: |
           PARAMS=""
-          if [ -n "${{ inputs.parameter-overrides }}" ]; then
-            PARAMS="--parameter-overrides ${{ inputs.parameter-overrides }}"
+          if [ -n "${{ secrets.parameter-overrides }}" ]; then
+            PARAMS="--parameter-overrides ${{ secrets.parameter-overrides }}"
           fi
           sam deploy \
             --stack-name ${{ inputs.stack-name }} \